我正在使用下面的教程来实现一个Selify关键字驱动的框架：http://toolsqa.com/selenium-webdriver/keyword-driven-framework/set-excel-apache-poi/
对于要求使用ExcelUtils类创建“util”包的部分，我遵循了从向项目库添加JAR开始的说明。
此JAR用于apache-poi-4.0.1：poi-4.0.1.jar库。
但是，即使有这个库及其附加的源代码，类XSSFWorkbook、XSSFSheet和XSSFCell也不存在。
所以我的问题是，我错过了教程的哪一部分？或者我错过了哪个图书馆？
我在JRE JavaSE-1.8中使用的是Eclipse Oxyon
包实用程序；

import java.io.FileInputStream;

    public class ExcelUtils {
        private static XSSFSheet ExcelWSheet;
        private static XSSFWorkbook ExcelWBook;
        private static XSSFCell Cell;

        //This method is to set the File path and to open the Excel file
        //Pass Excel Path and SheetName as Arguments to this method
        public static void setExcelFile(String Path,String SheetName) throws Exception {
            FileInputStream ExcelFile = new FileInputStream(Path);
            ExcelWBook = new XSSFWorkbook(ExcelFile);
            ExcelWSheet = ExcelWBook.getSheet(SheetName);
        }

        //This method is to read the test data from the Excel cell
        //In this we are passing parameters/arguments as Row Num and Col Num
        public static String getCellData(int RowNum, int ColNum) throws Exception{
            Cell = ExcelWSheet.getRow(RowNum).getCell(ColNum);
            String CellData = Cell.getStringCellValue();
            return CellData;
        }

    }